Specifically, though not exclusively, the invention can be advantageously used for collecting loose material in granule or powder form from a store and convey it elsewhere. A typical example of application of the invention is in transporting loose granules or powder material from a collection hopper or a ship's hold.
The present invention specifically relates to a device comprising a tubular outer protection casing, having a first part which is axially rotatable on command with respect to a second part, in which the first part is provided with at least one opening through which the material can be introduced into the casing. A screw spiral, located inside the casing and being coaxial thereto, can rotate on command about its own axis and thus transport the material in a parallel direction to the axis of the screw itself.
A screw conveyor of this type is known, for example from Italian patent IT 1,269,273.
The prior art further teaches a screw conveyor for collecting loose material from a store, having one end for inlet of material which during use is sunk into the store of loose material. The inlet end exhibits a free length of screw which projects axially from the casing and which operates on the material to force it to enter the inlet end.
Also known is a transporter which comprises, instead of the free length of screw, a screw which is destined to be buried in the pile of loose material to be conveyed. The external screw is coaxial with respect to the screw operating internally of the casing, and is commanded to rotate in an opposite direction to that of the internal screw. The external screw transfers the material towards the inlet end of the casing, where the material itself can be drawn into the internal screw.
The known conveyors as described above all have a relatively poor performance, especially as regards their efficiency in actually collecting the loose materials from the pile.